Gentoo is a great distro, if you want to have full access to all configuration capabilities. It has a very good package management system. It is also the perfect distro to learn linux. A major disadvantage of gentoo is the time it takes to compile packages. Imagine you visit a customer and need another browser on your laptop. You don't want to compile this package for half an hour. It is possible to install precompiled packages, but there are other distros which have better packages management systems for precompiled packages. An update of your system can also take several hours. The installation process on your PC / laptop is also very time consuming. But there are many people with gentoo installed on their productive systems and are happy with that. Once installed / configured, it is a very stable distro.
Raspberry Pi 4 with gentoo is the perfect combination to learn HW and SW. If your installation is broken, copy it to your SD card again. You can easily switch to other distros by replacing the sd card.
I've got a laptop with Ubuntu LTS to get my work done, which I also use to cross-compile the SW for the target (rpi).
-> see wiki.