So are they still running Alfa equipment until Audi takes over?

There is no Alfa Romeo equipment and there hasn’t been in decades. You got fooled by a mere branding deal with Sauber.

Element does not require a phone number.

Neither does Telegram since last year: https://www.theverge.com/2022/12/7/23498236/telegram-fragment-phone-number-crypto-verification-monetization

Signal literally exists. Free.

Signal has fewer features than non-premium Telegram. Both are open source, neither can be used with alternative servers (unlike Matrix).