You can now get an anonymous X (twitter account) but why would you? You may not need it now but redundant accounts come in handy later. So why now? X (twitter) is going through a transition which makes this method available. Do it now! because you won't be able later when you need an anon X account:

1/ set your VPN (better but not necessary) to the country you can get a telephone number for;
2/ get the X app with VPN running if you have a VPN and open app;
3/ use torbrowser (if you can) set on max shield and open tabs https://www.fakenamegenerator.com/ and http://www.guerrillamail.com/
4/ on the guerrilla mail tab goto Add-ons > NoScript and 'temp.Trust' guerrillamail.com
5/ add name to twitter app, this is not your @ and date of birth, note these somewhere as saving the fakenamegenerator tab will not save what it gives you;
6/ choose email and add the 'scrambled address' from guerrillamail but note both the scrambled address and the address in the welcome email as saving the tab will not save them and you can't add the scrambled address later as it changes and emails go to the one in the welcome email; get the code from the email (you may also need to temp.Trust jquery.com in NoScript) and add to twitter and go through the 'i am a human' check
7/ for a mobile number use a public telephone (street phone) number; it will ring and you only need 6 numbers that will be spoken; enter this into the X app;
8/ Once verified you can choose an @ name, use fakenamegenerator's if you're stuck
9/ don't go crazy, use app once a day and normal stuff so you're not flagged as a new dodgy account;