I would change the plugs and just get the transmission serviced. With 200K kms I wouldn't take a chance at a flush. Small dirt particles can get lodged into the valve body and give you grief. The only way to remedy is to remove and replace...not fun.
If the back shocks are gone, then the front struts are knowingly just as bad. Push down on a corner of the car at the back. If it rebounds quickly and settles down immediately then the shocks are fine. If it continues to bounce then get the shocks/struts replaced.
It won't hurt to get a front alignment done either. A good shop will tell you about any play in ball joints, and other components, so you can plan ahead a bit in terms of repairs.
'11 Ram SXT 4x4 quad cab - 5.7L V8; 128,200kms
'09 Malibu 2Lt 3.6L - 140,000kms purchased 1 March 2019
'06 Pontiac G6 GT - 3.5L V6; 162,000kms (rear ended 15 Feb 2019, and given totalled title by insurance)