The answer to your question is very situational. Is this someone you just met, are you currently friend-zoned, is this someone you’ve already been officially dating for a while?

In other words, what stage are you at in this relationship?

This sounds like a situation where you’re currently friend-zoned, so I’ll answer with that assumption.

You’re going to get a lot of opinions on this kind of question, one way or another, and some of this will just depend on what part of the world you live in. In my opinion, the best way out of the friend-zone is to just be direct and ask them out on an official date. This lets them know that you really are interested in them without putting too much pressure on them. At that point, it’s on them to figure out how to respond.

If they are interested, they’ll respond positively. If they aren’t, they’ll either say no, come up with excuses, or back out last minute. If they cancel on you, do they really sound like they sincerely want to go on a date with you? If you’re not sure, give them another chance, but if you find that they consistently cancel on you, then it’s time to move on/just keep them as a friend.

Depends on your interests:

As far as some sort of one-on-one support service, I’m not too sure of online services for that (beyond helping out in specific forums when people ask questions).

You can help out with a variety of different research projects over on the Zooniverse:
https://www.zooniverse.org/

You can help by contributing to the map around your area: https://www.openstreetmap.org/

Help out with research on wildlife in your area:
https://www.inaturalist.org/

Contribute to Wikipedia:
https://www.wikipedia.org/

If you feel passionate about consumer rights, you can contribute to the wiki here:
https://consumerrights.wiki/w/Main_Page

If you like to tinker with electronics, check out Fulu Bounties and get paid for helping to get around DRM on refrigerators or on an Xbox. This has the potential to help a lot of end users as well as prevent E-waste. https://bounties.fulu.org/

If this is someone you’ll be seeing a lot, it’s best to try to make peace with them. Instead of “pouring fuel on the fire” it’s best to “pour water on it”.

Personally I’ve had conflicts in my life with others, but instead of reacting negatively, I made an effort to do the opposite. In one case that resulted in a friend instead of an enemy. In other cases it has diffused the situation.

It helps to try to put yourself in their shoes. Try to understand where they are coming from and what has driven them to react like this towards you.

Volunteer for things you find interesting or fun.

Check out OpenStreetMap:
https://www.openstreetmap.org/
And help map out your area.

You can help out with a variety of different research projects over on the Zooniverse:
https://www.zooniverse.org/

Help out with research on wildlife in your area:
https://www.inaturalist.org/

Contribute to Wikipedia:
https://www.wikipedia.org/

If you feel passionate about consumer rights, you can contribute to the wiki here:
https://consumerrights.wiki/w/Main_Page

If you like to tinker with electronics, check out Fulu Bounties and get paid for helping to get around DRM on refrigerators or on an Xbox.
https://bounties.fulu.org/

Then of course there’s always volunteering for organizations nearby.

Why? I have reasons for each of these projects but for me it just sparks joy in contributing to projects that will help others.