I use that too but I generally find better prices on Google Flights. Also Skyscanner annoys me with how long it takes to give you prices as opposed to GF
Especially if you have loose plans and you don't want to commit to flights you might have to cancel. I'm planning to get the two extensions but I hope in the future borders between Thailand and Cambodia or Laos reopen so I can book a cheap bus journey and not waste too much money. At the moment I'm looking at the cheapest flights out of Thailand I can find on Google Flights
Can I ask what tourist visa you're applying for? I'm applying for STV and I don't have an onward ticket yet and I'd rather not have to book one just yet if not absolutely necessary...