I got the Deutschlandticket for May and am tempted to travel from Berlin to Stralsund. Using RE/RB for this journeh takes more or less three hours without any t

I got the Deutschlandticket for May and am tempted to travel from Berlin to Stralsund. Using RE/RB for this journeh takes more or less three hours without any train change (so not having to deal with the possible delay(s) and missing connecting rides), however I do hope the operator supports reserving a seat in advance with this subscription, cause otherwise showing up at the station not knowing for sure I'd have a seat would deter me from using this offer and instead just book ICE/IC (if any).