There's a potential that the government would approve "bubble tourism" countries which would allow people from certain countries to be able to travel in and out Thailand for tourism purpose without 14 days quarantine. If it happens it could start in August. However, this is just what they're still discussing, no decree yet.
You'd be exempted from overstay if you don't apply for extension before 31st July but you can also apply if you want to get it done. I do recommend for you to get it done by due date because all expats from the whole country will turn in to the immigration office after 31st July.
Generally it takes one month for the immigration to process your visa renewal application. I don't see there'd be any problem. Just go back on the appointed date to collect your one year visa.