How to get back into recording music?

I know you said Reaper is spartan but I'd recommend you give it a try. Kenny Gioia's tutorials will absolutely help.

Additionally, if it makes you feel at home these Logic Pro Themes for Reaper could probably help you recontextualize your old workflow.

Everything should likely work straight out of the box on Reaper. And generally speaking the community is q friendly on their forums.

Reaper may seem intimidating on the surface but the most difficult thing about it is the small period of time where you don't know much about it at all. Learning Reaper's workflow will take a bit of getting used to if you're coming from Logic but it will be worth it and it's only a short time before you're over the hurdle.

Adding to what @Kazarelth said, Kenny Gioia's tutorials are a great resource and you should not only use them during your "tutorial island" period but also as a reference while you get a better handle on things. I wouldn't personally recommend applying a custom theme until you're pretty confident in your ability to navigate the system though, it will just make things more difficult if you find a tutorial video for what you need but you have to figure out the UI disparities for yourself.

The more important aspect you should focus your efforts on is your monitoring & room acoustics - if you want to take your music seriously headphones are likely not going to cut it. Find yourself a well-regarded pair of studio monitoring speakers with an appropriate cone size for your room and a quality audio interface (I'd recommend MOTU M2 or M4 in your case if you're not satisfied with your current one) and learn how to acoustically treat your recording and mixing space - your speakers can only ever sound as good as the room they're in so I'd recommend a bit of heavy reading for that. The Master Handbook of Acoustics is the gold standard reading material - you may get thrown off by the physics thrown at you in the first few pages but you don't need to know that much, what you need to know is about room tone and how it relates to size, reflectivity of your surfaces, phase correlation/cancellation nodes and how to treat it. Once you've gotten past that you can use something like SoundID Reference to automate impulse tests of your room and correct for any further deficiencies.

I know this all sounds pretty intimidating, but believe it or not we were all in your position at one point and with effort and willingness to learn you can overcome it :) Assuming Reddit doesn't become another Digg incident in the near future, r/audioengineering as well as Gearspace and KVR forums can have some useful information (I wouldn't spend too much time on the last two unless you need something really specific) - otherwise feel free to fire any questions you have at me either here or in DM's.

Seriously seriously, ableton is by far my favourite for doing this. I know you said it didn't feel like it clicked, and that's eminently reasonable, but it really is good for recording and multitracking. Especially with the new comping features in Live 11 the piano roll view is really quick to get working in (press tab to switch between the loop view and this one).

I now just permanently have my pedal board connected to a line in on my audio interface, and have moved from writing maybe a few times a year to getting tracks started a few times a week when I feel like it (and sometimes even finished!)

In the end just picking one and sticking with it is the best idea, and making sure that going from idea to recording is as frictionless as possible will also help with getting creative quick!

I'm on FL Studio, works great for me and has a pretty good trial, so can just give it a shot. They also have a very fair pricing model with livelong upgrades once you buy even one of the cheaper editions and the option to upgrade your edition down the line if you need more options, or just buy specific plugins.

I can't tell you how close it is to logic, as I've never works with it, sorry :(

FL doesn't have the most professional reputation, but I've found it to be a very low stakes entry point with lots of tutorials and a not-too-steep learning curve (looking at you, Ableton). I will admit though, that it is better at piano roll midi songwriting with vsts than recording, but I've been recording our band things with it and it's definitely servicable.

I've been playing music for about a decade, but had never really recorded my work to the point I liked the end result. Unfortunately I can't give you any Windows recommendations as I use Mac, but in GarageBand what I've done is just make tons of projects with different snippets/loops. Then, I'll have a day where all I do is flesh out a snippet into a song. Something in my brain senses the soft deadline and gets me over the hump of getting it to a sharable point.

Equipment wise, I'm just using a Scarlett Solo plugged into my Mac. Haven't worked on getting drums added other than the built in loops. Are you able to make your drums sound like a normal 'rock band' drummer using the Maschine pad? Or would it be better to invest in an electronic kit once I get to that point? I used to play the analog drum kit, but it would always sound terrible when I recorded it with microphones.

don't know where to start

How about you just start minimal (like one single instrument, digital or physical), then build on it as you make time for it.

Example: hit record, noodle around on guitar for a while, stop record. then come back another day to layer on just kick and snare. Another day, mess around with a bass line. etc. Can even throw vocals into the mix. Doesn't have to be full-blown, multiple verses and chorus of poetic lyrics. Can just be you making a few audio snippets, and scattering them around repetitively.

I don't do much computer-generated songwriting (patterns, blocks, copy-paste, etc.), so I can't speak to that. That said, I use ardour, which is multi-platform and free to try.

Outside of treating the room, getting reaper, and maybe getting a new usb interface (I use Audient, get the usb c models) the most I recommend is getting stuff secondhand whenever possible and spending time recording and less time thinking of stuff.