Thanks Brajesh,
I would not have such a problem if WordPress would use the latest tinymce one but instead integrates tinymce 4.9 which is very old.

I am using the biography field already. This is currently the only solution to me using the cdn-tinymce version 7 – with the problem that it changes bullet lists to words line by line separated by an <br> on the profile view page. The edit page looks fine.

Furthermore I only can use it on the biography field with this code:

function antipole_remove_rich_text() {
return false;
}
add_filter(‘bp_xprofile_is_richtext_enabled_for_field’, ‘antipole_remove_rich_text’);

Another solution might be use it on the rich multiline textarea as you wrote.
BUT with using the above code I am only able to integrate tinymce 7 cloud on the biography field and not on the multiline xfield.
Without the code I cannot load it either on the bio nor on the multiline text field.

Do you have a solution to make it running on the multiline-textarea field? I would need to get rid of the integrated one and then load the cloud one.

Otherwise I only can prevent buddypress from changing the bullet lists on biography profile view page where I also have no idea how to.

Maybe we have a misunderstanding.
Have a look at this:
https://ibb.co/SrCSz5k

In the buddypress core there are code to put out a shorter version of tinymce with less items at the toolbar.
Check class-bp-xprofile-field-type-textarea.php
Anyway, I could also use the wordpress bio field which is a multiline textfield only without the editor.

Meanwhile I found a solution for the tinymce editor which is javascript driven unfortunately. This means a user can switch it off, then has the normal textfield back and can write thousands of words and crash the layout.

So let me ask again, is there any PHP solution for this texfield (multi-line text box or bio textfield) to limit the characters which beeing saved?

Regards Alex

Sorry, to ask once more.
No way to add some code wich is like “bypass submit for a field which is required and hidden”?

I saw conditional logic like that at the register pages from Gravity forms which sync to Buddypress xfields but to get this plugin just for that feature is beyond my budget.