In other words, there aren't many banks that let you take sensitive actions with just a browser and that's been true since the start of online banking.
These days they also apply differential risk analysis based on the device used to submit a transaction and do things to push people towards mobile. For instance in Switzerland there's now a whole standard for encoding invoices in QR codes. To pay those you must use the mobile apps.
Edit: people are getting hung up on the "never accepted browsers" part. It means they only use the browser for unimportant interactions. For important stuff like login or tx auth, they expect the use of separate hardware that's more controlled like a SIM card/mobile radio, smartcard or smartphone app. Yes some banks are more lax than others but in large parts of the world this was always true since the start of online banking.
That idea died for me long ago, I had used Android since 2009 till 2020. I gave up on the dream of a Linux phone. Ubuntu had a nice sleek Phone UI they were working on. The issue is if nobody builds the phones and no carrier cares, nobody will pick it up. You need to push yourself into the market.
Microsoft could fill this weird gap if they wanted to the key things would be they would have to truly open source the OS. I could see Amazon trying again, but they'd need to invest a lot as well. It's an uphill battle needing a serious flagship phone. Your other problem is most apps need to be migrated.