Choosing dumbphone. KaiOS, Nokia's S30, Symbian, something else?

I'm planning to get a Dumbphone, but I'm thinking about the options. Some companies are releasing DumbPhones with the KaiOS system that have a screen reader, however they might remove it.
That means that regarding these phones you would need to choose one with KaiOS 2.x (released before 2021). That version of KaiOS support 4G but I read that some apps such as alarms and clock are not working properly and the same happens with notifications. A thing that I love of KaiOS is that all apps are web pages made with html5, css, and JavaScript, so it would be easy for me to create apps for such systems. You also should be aware that Whatsapp calls won't work with phones with KaiOS 2.x, you might require a phone with KaiOS 3.x instead. Any page that work on XP using Firefox 52.9 or bassed browsers should work well with KaiOS. Another thing that I would need to consider is that there aren't a lot of KaiOS phones in European Union (concretely Spain) where I live, these phones are easier to find in India or similar countries.
Another option that I'm considering is some of the rebranded Nokia's imitations of classic models that have the S30+ system, but it's not very personalizable and you on't be able to get access to the internet. Another drawback is that these models have 2G only.
Fortunately, as far as I read, there's a phone OS that it's still much better than Nokia's S30 and probably better than KaiOS! I'm talking about the classic Symbian! Surprisingly there are still updated firmwares for it since some versions are opensource. Take a look to this,
http://www.symwld.com/delight/
So, Symbian might be more robust than KaiOS phones, but what about the screen reader and what about the accessibility there? And where could we get the screen reader for it?
There are still apps developed for Symbian, but it would be necesary to check the accessibility of them. However, maybe I could improve some of these apps since I have Java knowledge (I hate it). As a web browser, we would need to use Opera 12.x, that's the latest Opera with Presto engine. It has most of the html5 features, however there might be issues with JavaScript and css, but that's not a deal for me!
At least I plan to use that DumbPhone for some services (maybe whatsapp or telegram?), some web browsing and some kinds of 2FA authentication.
You could recommend also other devices, but please don't suggest anything related with Android (unless it is/feels like Android Donut/Eclair/other classic 2000 era smartphones) or IOS since it is really expensive. I might replace my samsung phone with another Android Nokia, and maybe use it as a secondary devices for stuff that the dumbphone can't do.