Is the rental income going into a bank account outside of Thailand?
Are you able to remotely manage the tenants and maintenance of the properties, either with or without a management company?
Do you do the admin, ie reply to emails with the tenants, use online landlord building insurance etc?
Do you do the bookkeeping and sending information to the accountant, or submit your tax documents yourself?
Do you have a tax return for 2024 or 2025?
If all are a ‘yes’ then you do not need a visa agency. You can apply as a remote worker.
Use Google and AI to find the relevant documents you need. Most are related to proving your sources of income, 500k+ savings and that you can work remotely.