A few things that should work:
1) UEFA, FIFA and all FAs join force to ban all those 15-20 clubs joining ESL from any involvement of local competitions (league & Cup) and international competitions (Wrold Cup & Euros) with immediate effect and possibly forever. Expel all of them in all current competitions with immediate effect.
2) All FAs issue life bans of players who has joined any of these 15-20 clubs to prohibit them from being signed with any football team in the world
3) All relevant governments in each country impose the strictest possible criteria for matches in this ESL, apply the most stringent standards in stopping any of these clubs growing in various ways such as stopping their stadium expansion, rejecting any kind of business proposals, etc. And impose new laws to guarantee fan ownership exceed 55-60% to reverse of any these proposals in the very near future.
Also can easily reject all visa application for players needed to join those clubs, as well as issuing bans of visas to players of those clubs who need to travel into the country.
That should make those clubs rot very quickly and disappear quite quickly too. Just punishment with pure greed in a pandemic when support and solidarity is needed.