The PSU you need is primarily gated by the graphics configuration.
Here is a handy chart:
http://www.realhardtechx.com/index_archivos/Page362.htm
A 550w unit will support perhaps a GTX1080.
GTX1070 should be an appropriate graphics card.
Future cards will probably not be more power hungry than the equivalent cards of today.
If the time comes that you want a GTX1080ti class card, you will want to change out the PSU, and you may find that ryzen is not the best for driving such a card.
Many games are cpu limited, think strategy, sims, and MMO.
It is the fast action shooters that need fast graphics cards.
Save your money until you find a game that needs more.
And FWIW, buy a liquid cooler only if you are doing it to get record seeking overclocks.
A good air cooler will be cheaper, more reliable, quieter and will not leak.