The tayga package is still in the Debian repos, just as it has been for over a decade. If you can't install it, something is wrong with your apt sources and you need to check those.
On a clean Debian buster system it will install with no problem.
root@vmtest-debian10:~# apt install tayga
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following NEW packages will be installed:
tayga
0 upgraded, 1 newly installed, 0 to remove and 21 not upgraded.
Need to get 34.3 kB of archives.
After this operation, 99.3 kB of additional disk space will be used.
Get:1 http://deb.debian.org/debian buster/main amd64 tayga amd64 0.9.2-8 [34.3 kB]
Fetched 34.3 kB in 0s (90.1 kB/s)
Selecting previously unselected package tayga.
(Reading database ... 37334 files and directories currently installed.)
Preparing to unpack .../tayga_0.9.2-8_amd64.deb ...
Unpacking tayga (0.9.2-8) ...
Setting up tayga (0.9.2-8) ...
Processing triggers for man-db (2.8.5-2) ...
Processing triggers for systemd (241-7~deb10u4) ...
Make sure you are using official Debian sources.
root@vmtest-debian10:~# cat /etc/apt/sources.list
# deb http://deb.debian.org/debian buster main
deb http://deb.debian.org/debian buster main
deb-src http://deb.debian.org/debian buster main
deb http://security.debian.org/debian-security buster/updates main
deb-src http://security.debian.org/debian-security buster/updates main
# buster-updates, previously known as 'volatile'
deb http://deb.debian.org/debian buster-updates main
deb-src http://deb.debian.org/debian buster-updates main