Been recording, and mixing my own stuff for quite a while with increasingly better results each album. Part of that is just experience and getting better and part of it is the huge technological leap that recording gear has taken in the last 20 years that makes it easier to get the sounds you want. Accumulating nicer equipment over the years helps too. I'm happy with my current setup and my last album I'm actually pretty happy with how it sounds. It's not pro level by any means and I'm sure a mastering engineer would rip it apart but for my purposes it works. I've learned a lot by watching pros on youtube also.
I started on a bulky Tascam 8 track. It was really cumbersome to record and edit mixes with that. I switched to Pro Tools until they changed to a subscription model and now its Logic Pro. With a DAW there are a million different plugins at my fingertips. I really only scratch the surface of what you can do with a DAW because my music is usually pretty straight on - guitars, piano, drums, bass, vocals.
I LOVE recording. It's "where the magic happens" a lot for me. It's an extension of the songwriting process as I don't usually fully work out all the parts of my songs until I record. Mixing, however, is super tedious to me. It feels like work and it's a lot of just check the boxes of getting EQ, compression, reverb, etc. right. I know some people enjoy that process and can get creative with it but I think that heavily depends on the type of music you're making. I can see something like EDM or hip hop being more enjoyable to mix. The sheer amount of time it takes to mix even one song can be discouraging to the normal indie musician. I have other sh!t to do but if I want the song to sound right it's like 2 hours just to get everything set up decently. Not easy to balance other life priorities when you're trying to create art.
All that being said I don't have any desire to outsource the mixing/mastering. I'm not looking to really make money off my music so I can't afford to fund that and it takes away from the DIY spirit that I enjoy about creating everything myself (even if it sounds like sh!t sometimes).