I see your point, but I can’t imagine this being a long-term measure. By the time international cricket is back to any sort of capacity I would imagine travel bans will be much lifted to allow for travel - otherwise, certain nations will have to give some umpires test debuts:
Australia - already have Oxenford, Reiffel and Tucker (plus Paul Wilson)
Bangladesh - no current test umpire (sharfuddoula? Not sure who else!)
England - Gough, Illingworth, Kettleborough and Llong
India - Nitin Menon has already officiated tests. Maybe recall S Ravi?
New Zealand - only Gaffaney (debuts for Chris Brown and/or Wayne Knights)
Pakistan - already have Dar. Ahsan Raza seems experiences enough for debut, plus women’s world t20 final shows ICC trust him
South Africa - only have Erasmus (Shaun George most likely to debut)
Sri Lanka - already have Dharmasena plus Palliyaguruge has TM experience
West Indies - only have Wilson, but Brathwaite would be experienced enough for a TM
Other than that, can’t see Afghanistan, Ireland or Zimbabwe taking on the expense at hosting a test at this time!