We don't need a personnal dummy dps tracker. Players who haven't any interest to learn a rotation will not waste theirs time going there.

A raid parser will show how is going the dps, healing and damage mitigation. Parser is knowledge.
Once you know your rotation is not going well, you have two options, learn or pray for help to finish content.

Parsers let good partys via PF don't disband because 1 player is underperforming. Bismark is the more recent content where bad dps could ruin a good group. Friends or party members, in this case, they'd recommend him a good rotation, don't spam one ability, use dots, etc.

All of us search diversion and fun encounters. Some players argue "i play as i want", "create your own elitist group", "my dps is Gud, you are the bad". We are working together to clear a content, why are you wasting our time? Our time is the same. If you want fun with zero improvement or spamming one ability, just create your own party. Oh...wait, if you put in a clear party 4 dps underperforming, tanks losing aggro and healers spamming aoe heals when not needed. Do you gonna clear the content?

No, then why do you want be the carried guy?