Preface, I am not an accountant. This is my perspective and you’re welcome to take the advice or not.
The benefit to HSA is that it’s funded with pre-tax money (same as FSA, but HSA rolls over year to year and usually balance over a certain amount is able to be invested into some mutuals/etfs).
Big benefit of FSAs is that they are pre-funded at the start of the year with pre-tax fake money. So that’s there for you for the whole year (just make sure it’s all used up by the end). Think of it as a 0% line-of-credit that is secured by your salary/job, resets every year, and is paid automatically by pre-tax dollars.
I don’t think you’d be coming out putting your tax refund into an HSA, unless you are counting the post-tax deposit towards this years tax burden. And if you are claiming standard deduction, it may not even give you very much of anything.
If you can float the cash, better to put your refund in a 1yr CD or something. Even into a HYSA, you’d probably come out ahead over an HSA.
Keep in mind you can only contribute to an HSA if you have a HDHP. If you don’t have an HDHP, it’s not an option.