https://repology.org/project/thunderbird/versions
It was recently added to arch and then manjaro unstable. It'll make its way to manjaro testing soon and eventually the stable channel.
If you want it now, there's the thunderbird-bin package in the aur.
Racknerd and lowendtalk have been around for a very long time. Racknerd has earned their good reputation over that time by being a stable provider with good support. The occasional great deal helps but none of it is too good to be true for anyone that has been following the vps space.