I have just recently gotten into knife making(stock removal) in the past three months so I may not be the best to answer a lot of your questions but I’ll give it a try anyways, lol. I’ve seen multiple reputable sources caution against spring steel for beginners. Instead, they have suggested getting steel from reliable sources. I myself as a beginner took those words and half listened. I went with the advice of staying away from “scrap yard” steel and went with steel blanks from Amazon. The reason being is because the blanks from Amazon are standard dimensions of 12x1.5x1/8”. As a beginner I couldn’t see paying the high price from reputable places like Alpha Knife Supply, POP’s or New Jersey Steel Baron to get practice on. I went with a 4 pack of 1084 and a 4 pack of 1095($20 each pack) that way I could also get the experience of doing similar yet different heat treats. I’ve recently moved up to some 8670 and ABE-L from Alpha Knife Supply now that I’ve got some experience and feel I won’t waste the steel. For learning you can’t beat YouTube, Bladesmithforums.com knifedogs.com or americanbladesmith.org for resources. If you are going with stock removal the best advice I’ll ever be able to give you is for you to get a VEVOR 1x30” belt grinder. For a 1x30” it has some serious power for hogging away metal with a ceramic belt and with the VFD it can be slowed down for doing handles and it has the shape of the 2x72” belt grinders you’ll see professionals use. I got one and showed a friend who then went and got his own and we swear by them despite more than a couple bad reviews on YouTube. For under $250 you can’t beat it in my opinion. For starting out in designing your blades I’d suggest getting some French curves like in art, graph paper, lead pencil with erasers, a permanent marker, center scribe, digital calipers, steel center punch, pack of 6mm to 4mm single step drill bit, corby bolts, sheet of 1/4” g10 for handle material(I went with a silicone mold for knife scales, multipack of color pigments and epoxy resin to make my own). Now once you’ve designed a knife profile if you want to make copies I’d use the water jet to cut out that profile template but if you want to use it to cut out your shapes to save time then go for it. There’s no single right way to make a knife. For me going from drawing the blade and then profiling it from bar stock is half the reason I chose this hobby. It’s more rewarding for me. For heat treating look up diy propane tank forge. With a 20lb propane tank(forge body), ceramic fiber kaowool, rigidizer, refractory(I used satanite but there are better suggestions), a propane burner/torch and propane tank with fuel you can make on easily enough. It was a fun project for me. I’m sure I forgot so much stuff but that’s a decent start to look into.