Don't forget to take into consideration the base station, aka signal tower, of the mobile network service provider when talking about higher CAs.
In the same way that buying a 5G device doesn't guarantee 5G performance in an area where the towers aren't configured to provide 5G access, the same...
Mukhang buong ethernet device ng router ninyo na po ang nasira. Mas mainam kung maipaparepair ninyo yan sa electronics specialist. Or replace it with a different router.
While this might not answer your question, you should be skeptical of ANY service before you commit entrusting your data to it. Read up on some reviews of the service here:
https://sourceforge.net/software/product/CBackup/
If you still want to continue then you can go ahead, but remember that...
Speed as in network throughput from the mobile ISP? You can't get more "speed" from what you are already getting from the stock firmware if you use OpenWrt because that is already the hard physical limit of the signal, not unless you can find proof that the stock firmware is doing some limit on...
You can opt to have it for free, which is available here as well. Just search for it. The only difference is that it isn't as polished (in terms of band locking, modem information, among others) as the one that I have created and am offering here.
Just send me a PM when you can.