Can I Extend My Non-Immigrant O Visa in Thailand Due to COVID-19?

I have a non immigrant o visa, multiply entry, until november 2020. i am german. my recent 90 days visa stamp ends on 29.5. - can i extend the visa at the immigration inside thailand (because i think it will still not be possible to make border runs). in ko samui or may be chiang mai later. and if yes, for how many days maximum can i get a extention? (i dont want to extend for one year, because of the 800 000 baht on a thai account requirement, 2 months in advance, its just not possible to do it in time anymore). and when i have to do it? less then 30 days before 29.5., right? merci.