ebay shows that older style thermostats are for sale:

https://www.ebay.com/itm/1261953615...MFFCA%2BWcg%3D%3D%7Ctkp%3ABk9SR6L_tOf-Yg

We should not lump all digital thermostats together - a portion are probably superior and have stable temperature measurements.

I would avoid Venstar brand,
even though they have extensive internal adjustments and “calibration” features in their menu of options