Glad that helped. 
Bit of a bug going on with grub & btrfs currently.
Method I've used in the past:
These instructions are from a while back when I was using Manjaro (modify for your current kernels).
How to force grub to load a specific kernel at boot.
For some reason grub doesn't at times want to behave and respect my settings to boot the last used kernel. I find it quite annoying when grub mistakenly boots me to another kernel I don't wish to use. If you find this behavior annoying as well, you can force a specific kernel selection as the default grub boot option.
How to hard code which kernel should be the default grub boot option:
Using this method will require occasional updating if you add or remove kernels. If the entry order of the kernel changes, you will need to modify /etc/default/grub to reflect any changes.
To change the default kernel boot order, edit /etc/default/grub and change the value of "GRUB_DEFAULT=":
Example (using numbers):
GRUB_DEFAULT="1>2"
The last number reflects the position of the kernel in the boot entry list, (numbering starts at 0).
You can find the correct kernel boot entry number by searching /boot/grub/grub.cfg with this command:
sudo grep -Ei 'submenu|menuentry ' /boot/grub/grub.cfg | sed -re "s/(.? )'([^']+)'.*/\1 \2/"
The output will be similar to the following list of kernels with their respective boot order.
menuentry Manjaro Linux
submenu Advanced options for Manjaro Linux
#0 menuentry Manjaro Linux (Kernel: 4.20.17-1-MANJARO x64)
#1 menuentry Manjaro Linux (Kernel: 4.20.17-1-MANJARO x64 - fallback initramfs)
#2 menuentry Manjaro Linux (Kernel: 4.19.36-1-MANJARO x64)
#3 menuentry Manjaro Linux (Kernel: 4.19.36-1-MANJARO x64 - fallback initramfs)
#4 menuentry Manjaro Linux (Kernel: 4.14.113-1-MANJARO x64)
#5 menuentry Manjaro Linux (Kernel: 4.14.113-1-MANJARO x64 - fallback initramfs)
#6 menuentry Manjaro Linux (Kernel: 4.9.170-1-MANJARO x64)
#7 menuentry Manjaro Linux (Kernel: 4.9.170-1-MANJARO x64 - fallback initramfs)
#8 menuentry "Memory Tester (memtest86+)" --class memtest86 --class gnu --class tool {
If you wish to make kernel 4.14 the default boot kernel in the above list, then you would want to add a 4 to GRUB_DEFAULT=.
Before you do any editing, make a backup:
sudo cp /etc/default/grub /etc/default/grub.bak
Then, edit:
/etc/default/grub
Set the default kernel by changing the "GRUB_DEFAULT=" line to match the kernel you wish to boot:
GRUB_DEFAULT="1>4"
In the above command, the 1> enters the advanced menu, and the 4 selects the kernel version to boot. It is also necessary to include the above numbers in quotes.
It is important to note that for the GRUB menu entries numbering starts with 0. Therefore the 1 above points to the grub Advanced menu. As a precaution, you may want to set GRUB_TIMEOUT=5. This is in case your entry mistakenly selects the memory test instead.
When you have finished making the edit and saved the changes, run:
sudo update-grub
Then reboot.
As I stated above you will obviously need to modify this for Garuda.