Not owning RE I’ve never tried, but I would follow the same logic as with any other appreciating/depreciating material asset above a few K’s
When owning a vehicle you e.g. may want to typically evaluate the depreciation as unrealized loss (you’ll realize it once selling). With a property the same can be done.
For simplicity (and also because it doesn’t really matter unless you’re leveraging the appreciation) your idea of doing it only with official numbers from a bank (i.e. potential buyer’s representative) is correct.
The frequency of recording changes in asset value in my opinion should follow the asset liquidity, with stocks being the most liquid and RE the least (well, unless you own art or old-timers, etc. ).
Take care only of timing the valuation with your FIRE magic number, and whether you intend to sell (=adds cash towards your FI target), rent (=expected cash flow minus taxes, maintenance, etc.) or live in it (=lowers your SWR needs) since property swings can be a biiig chunk.
I am very keen on trying beancount, but didn’t have time yet!