I would like to know if there is a way in sentinel hub to share collections, specifically collections with BYOC data, with other sentinel-hub users. And if there is the way, which is the most recommended plan for it for both, the one who upload the data and the one who is using sentinel hub to check that data.
There are two ways to share the BYOC collections. Regarding the situation you mentioned, one uploading the data and the other checking the data, I would recommend sharing it using our OGC services.
To do it, you need to create a configuration of the visualisation of your data in your account from the dashboard and share the ID with another user, who can use it to access the visualisation layer you created through EO Browser and have a quick look at the data. For more details, please follow our OGC API with QGIS integration webinar.
Another way is to share the BYOC collection ID with another user, which will give fully access to your BYOC collection, i.e., downloading the actual data with Processing API. Note that BYOC collection ID is confidential and whoever has the BYOC collection ID can fully access your BYOC collection. Please be careful whenever sharing it with someone else.