At the moment I daily drive a very modest system. I use an Asus Zenbook from 2019 that I purchased from Newegg. I have distro hopped between Mint and Ubuntu, but have recently come over to Manjaro to give Arch a try. Moving over to Arch has made this system very quick. I noticed an improvement in battery life and boot-time. Manjaro seems to have quite extensive community support as well so any issue I have come across is addressed with a quick search.
Manjaro seems to have a lot of UI customisation features. Customising the UI is not something I have ever put a lot of thought into. My workflow is pretty uninterrupted working with something that is very Windows-esque. It is actually impressive how much more advanced Manjaro is compared to other distributions. More than likely this has existed on every other distribution I have used, but I have just not cared enough to look.
In terms of sotware that I use I do not use anything too obscure and utilise what I would consider to be already popularised alternatives:
WPS Office - MS Office alternative
GIMP - Photoshop alternative
Firefox - Edge / IE alternative
Torriential - P2P software
ZNES - SNES emulation
Using FOSS alternatives, I cannot say that I have had any problems. Most well-known FOSS projects are well documented and have extensive community support networks. In fact, When troubleshooting Window's issues recently I found my search results were populated by official support people reaching out across various forums giving the same solutions that didn't work for me. Compared to the community support availiable for FOSS there is a lot of diversity in solutions and you will most likely find your solution.
In summary, I use a pretty modest system with pretty unremarkable software.