Kerbalism VS ContractConfigurator

There's a known bug where that option doesn't work. But you can disable the notifications for each vessel you launch. https://github.com/Kerbalism/Kerbalism/issues/812

If you want to change up how science works, I'll recommend Kerbalism. Makes it so experiments complete over time, some within minutes and others can take years. It also adds life support mechanics, radiation, and some other stuff.

My all time favorite is Kerbalism. It doesn't make it easier, but I think it makes it more interesting/fun, especially for manned missions. It reworks the science system, and has good life support and ISRU options.

+) someone opened an issue on the GitHub page but his problem isn't the same as mine https://github.com/Kerbalism/Kerbalism/issues/823

For career mode: Kerbalism. Reworked science system that makes it much more interesting, and good life support and ISRU options.

In terms of remaining mostly stock, I'd recommend Kerbalism and Contract Configurator with a few contract packs (second comment has a list) that fit your playstyle.

Install Kerbalism for food/oxygen/radiation/etc.

Adds things such as radiation, and more notably, needs for your kerbals. They need food, water, and air. That and more.

In terms of remaining mostly stock, I'd recommend Kerbalism and Contract Configurator with a few contract packs (second comment has a list) that fit your playstyle.

Contract Configurator Wiki

Also contract packs can be customized by creating/changing cfg files with a well documented API