1.9 SDI hard clutch

the clutch pedal on my 1.9 sdi polo 2006 is prettY hard, it has a lot of free play at the beginning and it engages at the very end but it does not slip and works fine besides the mentioned perks.
It has at least 150 000km
do you think it is time to replace the clutch?
Do i maybe need to do something with the flywheel also?
There are slight vibrations if i release it quickly at low rpm instead of slowly at higher rpm in which case i avoid the vibrations.
Which clutch would you recommend, sachs luk valeo or something else?
Do i need to bleed the clutch cylinder?
I also need the o ring for the gearbox and the bearing of course? Do i need the new gearbox oil if i replaced it about 70 000km ago?
Do you know of any diy guides to replace the clutch?