Managing Speeds With Fast GA Aircrafts

Im flying the TBM 850, sometimes on busy events in big airports where 99% of the traffic are jetliners.
Now, the TBM is very flexible in terms of speed and if flying without any traffic considerations, the speeds can be varying alot in between the stages of flight.
For example: Cruising at 180 kias then descending with cruise power and reaching 230 kias.

Now i wonder how it goes for the controllers out there who need to merge me with the other traffic, because i was flying into a busy event the other day and the controller asked me about the speeds that are available for my aircraft and twice about my current kias, before and after he gave me holdings, at which i did at 140 kias instead of 200 kias cruising speed to save fuel.

So my question is, should i try to fly as predictable as possible and try to imitate an airliner as much as i can or its not that critical for the controller?
Or maybe there are even procedures regarding such aircraft types?

No, it’s literally the controllers’ job to fit aircraft of different performances into their sequence (that’s probably why you were asked about the speeds you can make, too - that’s how controllers can get the data to calculate the necessary spacing during intercept to maintain separation on final). Of course flying an aircraft that’s significantly slower or faster than the rest of what ATC is dealing with may mean that ATC first has to build a sufficient gap which may take some time, but if ATC needs you at a certain speed they will tell you (again: that’s why controllers ask what speeds you can do if they’re not familiar with your type’s performance).

As Avi has said, but in regards to predictability, I’d say yes. Constant speed is ok, but wild variation would not be in my opinion. I only mention this as you mentioned predictable.