During COVID, which Schengen Zone countries can be entered through non-Schengen corridor countries, without quarantine? (April 2021)

As a resident of Ukraine (US passport holder), I'd like to know which Schengen Zone countries can be entered (I'd like to avoid the possible war in Ukraine, I assume border guards would currently look at my reason for entry as "for tourism purposes") without requiring quarantine time, when entered from a corridor country.

For example, Malta lists that travelers from Turkey can enter, assuming they've been in Turkey for the past 14 days.

So one could visit Turkey for 14 days, then visit Malta, then presumably visit other Schengen Zone countries from there.

I'd like to know if there are other similar "corridor countries" options available to enter the Schengen Zone, that allow bypassing quarantine time (COVID tests are no problem).