This is a topic that has a lot of differing opinions, but one things for sure there's many good options around these days so there something out there that will suit what you want.
You shoot in RAW and are after simplicity so the GIMP (freeware) whilst really good may not be suitable. There are free versions of RAW processors but I have no experience with them so will leave the feedback to others.
I used to use Lightroom and Photoshop but was not interested in a subscription.
I now use a program called On1 PhotoRAW. It's a purchase that gives you the program as a standalone product without a need for an ongoing subscription. The price is normally $99 but is currently $79. This is for the 2020 version released in November last year.
It is very good, it can do basic processing and complex processing so it's something you can grow into. They do lots of video guides for how to use the program. There are updates over the 12 months the program is current then they stop updating when the new program is released (usually each November). The good thing is the program continues to work and you own it forever.
Good luck with the decision.
Tas