I have had various amps and preamps over the 55+ years in this hobby. Almost all of it has been tubed and the times I delved into SS units, they didn’t last long in my system...back to tubes I went.
A tube preamp is a very good way to start, a no brainer, but in my experience the power amp contributes more to that tube sound than a preamp so if you really want to experience what tubes will do for you, then consider that. Also buying tube gear and having a specific expectation that it will sound a certain way can be a bit of a crapshoot. For example
#1 Some tube gear is voiced rather neutrally while others more colourful.
#2 Most modern tube gear is more neutral than 25 years ago
#3 Tube type used makes a difference. For example a tube power amp with 300B output tubes (not enough output power for you anyways) will sound very different from one with KT88 output tubes.
#4 Actual tube brand makes a difference so for example a British Mullard EL34 will sound very different from a Russian or Chinese modern EL34
Personally I have some Quicksilver Mid Mono power amps that I really enjoy. It can run EL34, 6L6, and KT88 tubes and each has it’s own sound, yet they all sound very good.
I agree with a previous poster’s suggestion to get a power amp with only 4 output tubes, much easier and less costly to retube and manage. This type of amp would typically give you 40-55 watts/channel. I have run speakers that one would consider a not so great match with these type of amps yet unless you are in huge room and want to play at high levels, it can still work very well if not optimally. At least then you can decide, if you like what tubes bring to the table, to go bigger.
I hope all this info has not overwhelmed you and scared you off tubes, it’s really worth it. BTW, I’m also a Bimmerlover, we have 3 in the household, and with spring in the air the Z4M is getting out in the sunshine a bit lately!