Sometime I'm amazed when reading this forum.
Since I got my DIY MK3 in january I print almost every day with no particular issues, only done some improvements, printing mostly PETG, but also ABS, ASA, Flex, Carbon, the only problems at the begining was due to my lack of experience because it's my first 3D printer.
As a Linux user since 20 years, I'm very concerned by open source and it's one of the reason I choosed PRUSA.
No it's not perfect and could be improved, but you are free to make all changes, modifications you want, and no need to accept any licence agreement.
Come on, let's get real, If you are afraid of having potential issues and don't want to put your hands under the hood, just don't buy an open source printer.