Sample slowley speed up?

I would like to cut dance music for a formation. This means that I have, for example, a rumba with 100 bpm and a chacha with 124 bpm that are to merge into each other.
I could do a hard cut or crossfade. The problem is the different speed.
Is there a way to change the speed of a section slowly? With Stretch Mode I managed to change e.g. 2 bars from 100 bpm to 124 bpm. However, this happens in jumps and doesn’t sound very harmonious.
So I am looking for a way to slowly speed up a sample. Does anyone have an idea what keyword I can search for, or even an idea how I can do it?
Thanks a lot

If you set the project tempo to 124 bpm and set the grid to 1 beats, it should be possible to stretch the 100 bpm tempo loop to the desired length

I don’t think this is possible for audio, changing the BPM will only affect MIDI regions.

I found this related to Audacity. Not sure if it’s exactly what you want:

That’s what I did. I used this video to determine the tempo or the bars: Tempo Mapping in Mixbus - YouTube This also works, but the result is not very nice to listen to. The change sounds very rough.

Thank you, I think I was looking for something like that. I will try that today.

I found this: The Ardour Manual - Setting Up Stretch Options

“This means that should session’s tempo change over time (in either ramped or constant mode), all audio clips will be re-stretched to accommodate for that.”
I have already worked with the ramp. Maybe the speed adjustment works with it. I will try that again.

This Option is only in the Ardour 7 possible. And i belive 6.9 is the better option at the moment.