Help a n00b upgrade a previously intel i5 4950 build to AMD only? Compatibility questions and whether to wait? Advice please!

Hello all, I built a computer back in March of 2015 with the intention to upgrade later. 5 years later, here I am having only upgraded my GPU. I recognize AMD is superior to others, now, though back when I originally built my rig I didn't know really much about anything and I had a friend help recommend the parts for the type of gaming I do. I upgraded my card from RX 290 series to RX 570 series because I had the extra money around cyber Monday last year. I shortly later discovered my hard drive wasn't doing great and was starting to give out (which is reasonable after 5 years) so I just got a Seagate one that was on special and it works great. However it must be faster than my old hardware because I am noticing a lag not from the drive but the processor seems to be taking awhile to think when I retrieve files or start programs and I have a ton of lag with splitscreen anything. Loading screens are so long.

I discovered the issue is my processor is not very fast. I am actually very disappointed in the processor I have. I've compared the Intel i5 4690 I have with even the oldest AMD available to me now (not that I'd buy it, but just to see) and it's just so sad. AMD is less expensive and more energy efficient but also works better and faster. I honestly feel a little ripped off. So, I wanted to upgrade my processor to a better AMD. I ordered a Ryzen 5 3600X that was on sale, sounded great to me. I attempted to fit it and it does not fit in my motherboard whatsoever! Upon doing yet more research I discovered the Gen difference and that most motherboards are literally intel specific (wtf is that BS) including the one I'm running! So I guess I have to get both a new motherboard and processor. I've been researching lately my options for motherboards that fit my specs with AMD 3600X and I came to the conclusion the B450 is probably my best bet, by MSI preferably. I was going to order it earlier and did some more final research and just found out that another gen of cpus is set to be released? But do we even know when this is? and how do I know stuff I buy now will be compatible with that, when I upgrade again? I don't want to purchase something now to just have it become trash in a few weeks, or to have to rebuy more parts. I don't know if I even need the newest, latest and greatest stuff, because I really like the Skyrim/Fallout/Civilization/League type games so it's not like I'm doing any of the battlefield/shooter things or any of the open world expansive No Man Sky or ARK. I just want something affordable, and middle ground, without having to rebuy all the parts in my computer. My budget varies, it can be higher if the stuff will be future-proof but if it's a get-it-now then it's obsolete then my budget is actually quite low on stuff and I will save the extra money and upgrade again later. The thing is, I have the money available to upgrade now and I need the new processor and mobo now. I can't/won't wait months to years especially without a guaranteed drop date. I just don't want to buy what I am looking at now and be disappointed when they release new cpu's that don't fit and I have to spend another 500+ dollars on a processor/mobo set.

My current/obsolete build:

• Intel i5 4690 @ 3.5ghz
• MSI Z97S SLI Krait Edition
• Radeon (was 290 series, now 570 series)
• Seagate mechanical hard drive
• 8 GB Adata RAM sticks, in the form of 2 4gb sticks.

My planned build:

• AMD Ryzen 5 3600X
• MSI B450 Pro Carbon Max
• Same GPU and hard drive
• Not really sure what to do on the RAM, I know there are different pin numbers but I really don't know much on this either, so I would probably get the mobo and figure it out from there if my current RAM is not compatible.

Can I just get some general advice/knowledge/tips/info/etc on all of this? Should I wait or is it even worth it? Thanks!