I want to claim an inactive gamertag

You can't.You can't even be certain if the gamertag is inactive or not.Gamertags are used on other services,not just xbox live,so just because a tag has no activity on live does not mean it isn't being used somewhere else on one of Microsofts services.

The earliest any unused tags will be freed up is around August 2021 so you'll just need to keep checking after that date.

At my understanding this was set for the use of microsoft account, for services like outlook, where indeed says that you need to use it every two years. But the gamertag expires after 5 years, you can google it anywhere, there was a lot of news back on 2016.

I remember asking a long time ago to support what would happend if theres a gamertag but the email was expired. They said that the gamertag would remain there even there's no email.

Ohk so how can I know how long it has been inactive for?

It's 5 years, not 2. Alternatively you can get that gamertag with a suffix number behind.

see
this tho
Thats for Microsoft accounts. Not Xbox Live accounts/Gamertags which fall under different timeframes

It's 5 years, not 2. Alternatively you can get that gamertag with a suffix number behind.

see
this tho