I don't remember who asked this, and if it already got resolved but if not the following might be useful for some:
In redmine you could "watch" tickets and have them visible from your profile. (do I remember this correct? However, someone asked for a function such as this in Gitlab)
In Gitlab you can do this by adding a reaction to an issue and then search for issue with My-reaction = [what ever you choose]
Issues that you've been watching in readmine should be migrated to Gitlab with the reaction "star" (if I'm not confusing).
You can also watch those issues through a RSS reader. To do so you just do your custom search, and then click on the RSS symbol.