Lol, yes, definitely get certified!
Buy
A comfortable mask
A comfortable set of fins
Rent
Everything else.
Diving certification is always 100% worthwhile, even if you only dive another 10 times in your life.
What you learn is ridiculously amazing.
Btw, I'm on dive 1500+, at least.
The kicker is the thousands that you spend on new toys/equipment that you might use 10 times in your life.
A mask and fins you like that fit well will always be a good purchase. You want them to be familiar.
But the rest of it is often a complete loss in the return on investment sense.
Traveling on a plane with a full set of gear can be annoying. Especially with the newer integrated weights and BC's.
In a previous life, when weights came on a belt, tanks and weights were always provided at the destination.
Been years since I dove recreationally.
Diving in fresh water can still be lots of fun. There is still plenty of life.
Just less technicolor colors.