I've used the BRRR strategy multiple times with some success. Covid made it harder because banks tightened lending for awhile earlier in the year. I don't know if this varies by state (I'm sure it does to some degree) so call around and ask some folks in your area but this is what I found.
1. Conventional banks are still hesitant to lend on investment real estate at this point. They will do a refinance after the six month seasoning period (that hasn't changed) but only up to purchase and renovation cost. In other words, ARV doesn't matter as much as it did pre-covid.
2. Many private money lenders are now requiring some sort of seasoning period though the time varies. Most are less than six months but you pay for that with much higher fees, interest rates, and points. Cash flow has to be strong in order to entertain this option.
3. Things are moving slowly so expect delays. There are a lot of people doing refinances and some courts are closed or working different schedules so it takes longer than usual for things to get recorded, etc. At least that was my experience. My last deal took a month and a half to close.
A few banks I've worked with are:
PrimeLending (conventional)
Lending Home (private lender with 30 yr option)
Visio Lending (private lender with 30 yr option)