If you are married in Germany, you must apply through Deutscher Tourismusverband (DTV).
Please keep in mind, that you will require to submit your Arbeitszeugnis copy and make sure you have a copy from your local Sparkasse which has at least 15 000 Euro in accounts for the past 6 months.
Or just read the DTV Visa rules and use search in the group.
transfer yes but makes sense for larger sums only; QR-scan limited to business payments (no personal QR-scans). Debit cards work everywhere, including Thailand
there is no need to get a 6-month extension. Just use a proper agent and get it done through bank salesforce that works with remote clients (eg open account at your home)
they act randomly. We had 4 Bangkok bank accounts in the family. We brought same set of documents when accs got frozen. 1 account on DTV got unblocked, 3 other remained suspended