What level do I go up a ring in Xbox Insiders

Going in out the ring was boring, but once inside the ring, I was doing other things like browsing the Internet etc.

This is got me to Level 100 easily.

Yes I'm the Xbox Insider

I'm currently in two rings

I'm level 5 on insider

You need to Register in the Insider Hub App, Then you will be placed in a testing ring.

You will possible be placed in ring 4 or 3 and then you just need to keep doing Surveys and leave feedback within the app to level up then you will get a messages after possible several month inviting you up to the next ring

General: To level up and get stronger.

Ambassador Xp: To reach higher tiers and unlock rewards.

Insider xp: To earn the right to join higher insider rings.

The Insider Program doesn't operate on invites from other members in that specific preview ring. So the information you received from a support agent may not be entirely correct. Each preview ring has a limited number of "seats" open at any one given time.
Delta through Beta are all open access to the general public and your qualification for being able to join those rings are based off of your activity in the Insider Program, level in the Insider Program, and the diversity of what you do on Xbox Live. They
occasionally do a survey on the Insider Hub app asking for people who would be interested in joining either the Alpha or Alpha Skip-Ahead rings. Both of those rings are invite only but, the invites only come from Microsoft themselves via the Insider Hub app.
Being an Xbox Ambassador may help you get into those rings, as it may you look better and more qualified, but it doesn't guarantee you a seat. As a side note, the survey also doesn't guarantee you a seat when they send it out. Its essentially a first come
and served basis.

I'm level 12 in the Insider Program, that's over about 2yrs of activity and I just recently got invited into the Alpha Skip-Ahead ring. I can confirm you cannot invite other players to join the ring and it has to be done by Microsoft through the team that
runs the Insider Program.