haha told you the DAW itself can be the reason. Reaper is extremely customizable and you can go all geeky with it, but the UI design is not so intuitive imo. It has great community support and practivly free, though. I also use Reaper when I'm on my Windows machine. I recommend you look for more intuitive looking themes on its website to help you out. https://stash.reaper.fm/tag/Themes . Glenn Fricker uses Reaper in his Youtube channel. I'm not the biggest fan of his mixes, but if you wanna familiarize yourself with mixing in Reaper you should check him out.
Now back to your v3 mix, I'm sure you are well aware that it is much better than v1 already. Here comes what I think is the hardest part of this track : Bass. Right now yours is quite boomy on the lowmid frequency. Make sure you boost freq. that correspond to the range of the instrument. Thing is Reaper stock plugins are all way too transparent (mathematically precise, not very 'musical'). This is where all those fancy third party plugins you may have already seen all over Youtube come into play. This noone can really help you, it's entirely your research and investment. for example check this out it may work for you https://forum.cockos.com/showthread.php?t=213501 . All I can say is reduce lowmid, boost the crap out of hi-end, highpass at 30Hz can get you atleast 50% there in bass guitar mixing. This is the part where you have to do your own Youtube research, and train your ears to be more sensitive to picking out frequencies. Say goodbye to enjoying your favorite record without criticizing its mix! (but don't worry, you'll come back to it later once you realize its actually yours that sucks). Psychoacoustics is one trippy rabbit hole, trust me it WILL drive you nuts but that's okay. Take frequent rests to avoid ear fatigue. It may takes you 10 revisions to get it right but then it's the best feeling in the world, you'll see! My very fist mix was also metal, and it took me ONE WHOLE MONTH to mix it. Now I only need a few hours to come up with the first version of a polished master. Learn your tools, read a TON of texts on what each processing module does, create presets, develop a workflow, your plugin arsenal will get huge FAST. It's very normal for new mixers to be very experimentative, but then again most will eventually strip down bit by bit, all into a very similar chain of processing. That's how industry standard workflows are originated. The more advanced you get the better you'll be at making the most from the least.
Now back to your v3 mix, I'm sure you are well aware that it is much better than v1 already. Here comes what I think is the hardest part of this track : Bass. Right now yours is quite boomy on the lowmid frequency. Make sure you boost freq. that correspond to the range of the instrument. Thing is Reaper stock plugins are all way too transparent (mathematically precise, not very 'musical'). This is where all those fancy third party plugins you may have already seen all over Youtube come into play. This noone can really help you, it's entirely your research and investment. for example check this out it may work for you https://forum.cockos.com/showthread.php?t=213501 . All I can say is reduce lowmid, boost the crap out of hi-end, highpass at 30Hz can get you atleast 50% there in bass guitar mixing. This is the part where you have to do your own Youtube research, and train your ears to be more sensitive to picking out frequencies. Say goodbye to enjoying your favorite record without criticizing its mix! (but don't worry, you'll come back to it later once you realize its actually yours that sucks). Psychoacoustics is one trippy rabbit hole, trust me it WILL drive you nuts but that's okay. Take frequent rests to avoid ear fatigue. It may takes you 10 revisions to get it right but then it's the best feeling in the world, you'll see! My very fist mix was also metal, and it took me ONE WHOLE MONTH to mix it. Now I only need a few hours to come up with the first version of a polished master. Learn your tools, read a TON of texts on what each processing module does, create presets, develop a workflow, your plugin arsenal will get huge FAST. It's very normal for new mixers to be very experimentative, but then again most will eventually strip down bit by bit, all into a very similar chain of processing. That's how industry standard workflows are originated. The more advanced you get the better you'll be at making the most from the least.