Hi Remi,
first - it's easier to follow a topic and maybe the way to find its solution if we stick to one thread at a time.
You sure don't want to look for hints & help in various places.
And it's easier for others to find help if they encounter similar issues.
To keep it here I'll quote your latest input:
remivill hat geschrieben: ↑04.02.2021, 23:28
Here you can see that the blocking nuts (for the transport screws) are touching the faceplate. I supposed they should not ? Unless you put the screws.
Is it normal ?
From what I see even if I try to adjust the suspension springs those parts are blocking the chassis. That looks like it cuts the possibility to get the platter higher.
I am desperate...
While in this other thread - "Braun PS 500 Plattendreher perfekt verpacken?" - have you seen
Phil's contribution?
I'll quote that here, too:
thebeathunters hat geschrieben: ↑14.06.2011, 01:12

thanks to derlange who was a big big help and support to adjust the level of my ps500 after some hectic transportation.
we borrowed on his technique for the best part but succeeded in a simpler way.
so here's "ps500 level-control for dummies"

phil
The only other reasons for your problem I can think of are
a) the hight (i.e. thickness) of the sub platter is not sufficient - maybe wrong sub platter (hi, experts: did Braun use different sub platters??)
b) the platter that came with the PS500 is the wrong type (hi, experts: is that possible??)
Yours, Gereon
edit 15:00: Now I can think of a third reason...:
These "nuts" (distance bolts?) you circled in red - I think they may were not screwed in originally.
(At least I've seen a similar chassis of a PS4xx without them.)
They look a little bit like these:
There should be a thread for the transport screws in the
sockets under them (
marked yellow):

Can you screw these nuts/distance bolts off these sockets?
edit 19:40: Got to say it again - this is not my turf, so these are just ideas...