The upside is 1) total customization, 2) if there is a problem you have a lot more power to fix it. There are just a lot more problems.
Here's a list of my daily Linux issues (NVIDIA driver required to use external monitors)
1. Resume from sleep causes browsers and electron apps to fail to draw anything. I have to close and restart them. I found a workaround for Chrome (turn on Vulkan) but that's not possible for Slack.
2. Periodically Linux reports I have no internal speakers and I have to kick pulseaudio
3. NVIDIA driver page faults several times a day requiring me to unplug, replug monitors and run xrandr to reconfigure the displays.
4. After an upgrade my system now boots to TTY and I can't figure out how to fix it.
5. Zoom annotations don't work
6. Discord audio didn't work until I found an obscure workaround.
7. External monitor detection doesn't work
8. The laptop display doesn't go into power saving mode ever
9. Usb devices have to be unplugged/replugged to be detected
10. Complete system crashes (hang with no recognition of any input, so no way to switch to TTY)
So, pros and cons.
edit: I should note that the last Macbook (2017 I think) would kernel panic randomly when connecting or disconnecting external monitors (like when going to a meeting).
I run an IdeaPad p400 with Ubuntu 20.04. Everything just works. Had a sager and a System76 that worked without issues, too.
Sometimes, it's the hardware that's the problem. Had a Dell and an HP for work that were so bad with Ubuntu that I had to give them up entirely for Linux machines.
Honestly, my next laptop is going to be a System76, top of the line model. If it can last as long as my Lenovo (2010, I think), it will be money well spent.
For GDB, the instructions on the GDB wiki should still work on Big Sur, and they actually last changed in the release before Catalina: