As suspected by OP, the hardware is 64 bit but it is running in 32 bit mode as mentioned in this [reddit](https://www.reddit.com/r/AndroidQuestions/comments/cn3pnq/does_samsung_galaxy_a10_2019_have_64bit_android/) which in turn refers to [geek bench](https://browser.geekbench.com/v4/cpu/search?page=1&q=a105) for proof.

Apps like [AIDA 64](https://play.google.com/store/apps/details?id=com.finalwire.aida64) can reveal this 

[![enter image description here][1]][1]

[Source](https://www.quora.com/How-can-I-check-whether-my-Android-phone-is-32-bit-or-64-bit?share=1) 

Also Antutu, if you have it installed, as [it is removed from Play Store](https://www.xda-developers.com/antutu-benchmark-removed-google-play-store/) 


  [1]: https://i.sstatic.net/ZQ2Vzm.jpg

As general info, see [How to find ARM processor version on android device?](https://stackoverflow.com/q/6630386)