Kernel upgrade

Hi all. 
I actually have Linux Mint Mate 4.9.0.13-rt-amd64 Debian 4.9.228-1
I would need to install a PCI Wi-Fi and all the ones I have looked at ask for kernel 5.1 or higher.  From what I'm reading I know that up to 5.10 is available right now and I have a slight idea of ​​what the upgrade would be like but since I have doubts and I don't want to break anything, I prefer to ask for your help.  I would appreciate if someone could tell me about the steps to follow as well as the commands to update the Linuxcnc kernel safely.

I take the opportunity to say that I have in mind a Ubit-AX200 802.11AX WiFi 6 (Intel AX200 chip) Does anyone know if it goes well or gives problems in Mint Mate 20?  They also have another model with a Gigabyte chip.

Thanks, Rober.

(Sorry it might be in the installatation thread)

It would be like this?

wget ftp.us.debian.org/debian/pool/main/l/lin..._5.10.46-4_amd64.deb

sudo gdebi linux-image-5.10.0-8-rt-amd64-dbg_5.10.46-4_amd64.deb

sudo apt-get update

Thanks tom.
Are you talking about 5.6RT? In the index it goes from 4.9 to 5.10 and in RT that I understand what I need for the machine I only see two, one with the dbg and another marked as unsigned, which seems to be only about 50M.
Maybe I am getting too complicated by entering things that I do not know completely when really all I need is a PCI Wi-Fi that goes well with what I have.
Would you be so kind as to tell me one?

The problem is that I currently have a USB wifi that is more intermittent than stable, not the wifi itself, hence I want to buy a PCI adapter.

What you say about the Tp-link I have read to you in other posts, the thing is that the USB Wi-Fi is limited due to the 5v and that makes it irregular and intermittent, that's why I wanted a PCI, which is why I am reading it is a bit of trial and error and crossing my fingers so that they work putting and go.
I had decided on the Ubit model mentioned in the first post, I have consulted them and the answer has been "you will have to compile your kernel, if it is not handled in Linux (in my case) do not buy it" which leaves me a bit in a position to risk buying one and see what happens. What is clear is that since it does not work simply by plugging it in, I will need help.

You can get the 5.1 kernel using Debian Bullseye as discussed in this thread.
forum.linuxcnc.org/9-installing-linuxcnc...-rip-install?start=0
The thread has been renamed so there is a bit of a preamble but I think we covered it. Bullseye was scheduled for official release tomorrow 14 August

Thank you very much for the info Rod. At the moment it seems that I have the kernel 5.10 without having destroyed anything, I will wait to have the PCI next week and I will try, let's cross our fingers.