You might be ok, but you’ll be leaving almost no room left. I have a TUF 3090 with a 375W power limit and an overclocked 5950x. Just running MSFS, my system pulls around 700W from the wall as measured by my UPS. PSUs are normally designed to be safe up to the advertised wattage, but I would be very cautious running near 100% at a regular basis.
One of the benefits of buying a new PSU is higher wattage capacity to allow for a higher power limit, and having one of the newest ATX 3.0 PCIe 5.0 PSUs that allow for a data communication between the PSU and GPU.