How Can I Extend My Stay in Thailand After My Tourist Visa Expires?

The question may be a little premature. I’m on a 6 month multiple entry tourist visa (now expired) - have the amnesty until 31 July. I need to stay until end of August so 30 days more. Is there a way I can secure that - normally I would have gone to Mae Sai over the border and back and got 30 days visa waiver. Just thinking it may be risky if they ask for covid test even for literally stepping over border for 5 mins. This all may be too early to worry about now. Thanks in advance for your support.