Over the past two years Tails has received 500k USD in bitcoin alone:
https://www.blockchain.com/explorer/addresses/btc/bc1qjg53lw...
You can also surmise that they receive ~200k/yr from official sponsors:
https://tails.net/sponsors/index.en.html
Then you have all the paypal, bank, cash donations.
Is it enough to add support for a second arch that is fully supported upstream (they ship a customized Debian)? You decide.