In most stadiums yes, but there will be some games with supporters I think. From what I saw in Europa league games, there was fans in Ukraine and Russia. Also, as I know Belarus and Faroe Islands allow spectators to visit stadiums. Maybe Israel to, they already had vaccinated quite big part of population. UEFA allows to fill up to 30% of stadium capacity. It's good feeling to watch game with real fans and no some artificial sound from FIFA games.
I’ve noticed this before at Euroleague basketball games in Russia, and at one point I thought it was some old videos - a bit of a weird situation, because from what I hear the vaccination rate in Russia is very low. I think we should let spectators into stadiums in those countries that have a good epidemiological condition, of course with the obligation to wear masks and a safe distance.
In my country, thousands of young people gather outdoors every weekend and the government does nothing about it - but at the same time, people are not allowed in football stadiums, which really doesn't make sense.