mikhett, in my experience a big part of the fun (and, the challenge) in building tube guitar amps is in the planning and then sourcing all of the various parts.
The really good news is that Hoffman stocks most of the parts needed. I was overwhelmed with confusion trying to select parts from places like Mouser, or DigiKey. But, Hoffman basically stocks only the types and values of components used in guitar amps. So, it's pretty much foolproof; the only big choice you have to make in his store is what brand of capacitors you want (and, there are no bad choices).
With a few exceptions, I've used Hammond transformers, and Hawk has the best prices. You can spend more on Mercury Magnetics, etc., if you want. Tubes are currently a serious challenge if you don't already have a stockpile. And, that's why a lot of kits are back-ordered.
Chassis and cabinets are easy enough to source, and folks here will make good suggestions based on experience. Mojotone and Guitar Cabinets Direct are good, and zachmdhunter on eBay for chassis. There are lots of others.
Anyway, the project planning and the sourcing of components is now a big part of the hobby for me that I really enjoy. I'll get an idea, start by choosing the tubes and appropriate transformers, and then post my ideas here on the forum. My projects usually go through a bunch of changes due to suggestions and corrections from the experts here. Then, when it's finalized I'll start ordering the parts. This is the stage of the project where I learn the most about what works, and why.
A kit will deprive you of all of that valuable and fun stuff.