I would still RMA it and then sell the brand new replacement in the MM.
Personally if buying a replacement I would go for a quality 750w to cover any future upgrades. After decreasing for several years component power requirements are shooting up again, just look at the consumption of the Nvidia 3000 series. Any of these should see you good:-
My basket at Overclockers UK:
The Bitfenix Formula Series 750w is the budget option but still a very good PSU. It's built by CWT, is gold rated and has quad 12v rails totalling the full 750w. The downside is that it's non-modular and has the shortest warranty of these units but still has 5 years.
The Phanteks Amp 750w is a bargain at the moment and is basically a Seasonic Focus Plus with a Phanteks sticker. Seasonic built, gold rated and has a single 12v rail of 744w. It is fully modular and has a 10 year warranty.
Corsair's RM series was redesigned and relaunched in 2019 and is now a very good PSU. It's a CWT built unit with a single 12v rail of the full 750w, is gold rated, fully modular and has a 10 year warranty.
I only included the Superflower Leadex III ARGB 750w as it was the only 750w Leadex III in stock. Don't get me wrong, it's a cracking unit, just that I hate RGB and it has no place on a PSU that ideally should have it's fan pointing down sucking cooler air from outside the case. It's obviously Superflower built, fully modular, gold rated and has a single 12v rail of 748.8w. It's warranty is lacking compared to the other big names but is still 7 years.
The Seasonic Focus GX 750w is one of the latest units in the Focus platform and is gold rated, fully modular and has a single 12v rail of 744w. It has a 10 year warranty but personally it has nothing extra over the Phanteks Amp 750w to justify the extra cash.
Finally is the Corsair RM750x. This is one of Corsair's best units and like a great many of Corsair's PSU's is built by CWT. Gold rated, fully modular with a single 12v rail of the full 750w it has a 10 year warranty.
I see no reason at all to spend any extra for a 750w PSU so that was as far as I went through OCUK's stock. If you want to consider future upgrades many motherboards now are coming with 8 pin and a 4 pin cpu connectors (EPS connectors). With that in mind all of these units have a pair of 4+4 pin EPS leads.