Hello and welcome to BW forums
PUPD really is hard work but try to stay positive. Have you kept any record of how many times you had to pick up on day 1 and how many times by day 6? I would imagine there could be some evidence in there to show that progress really is being made although when you are exhausted it can feel like none.
We usually do not recommend PUPD for babies this young and it is anyway a last resort method, however I see that you are also using shush/pat which is exactly what we would recommend and is suitable for this age. With shush/pat you do pick up if LO is very upset but otherwise you continue to sooth in the cot as much as is needed to help him nod off.
Please be reassured shush/pat is not considered a prop at all. It is easily weaned by reduction. So please feel confident to use as much shush/pat as is needed at this atage to get yoru LO asleep. You can shush/pat in arms until he is asleep then put in the cot and continue to shush/pat until deep sleep. Or if you are further ahead on the training than that you can put down in the cot when drowsy but awake and continue all the way to sleep and until deep sleep. Over time this can be reduced.
I suggest if possible find yourself a low chair or stool and see if you can make yourself more comfortable at the cot side - can you fit your arm thorugh the bars so you can sit low down rather than bending over the top?
A guidance activity time for LOs this age is around 2hrs so aim to have him asleep by this time. If this ends up longer because he is resisting sleep it's ok, this is to be expected during sleep training.
I am sure that over the coming days you are going to see some improvement which can really help to keep you motivated. Babies really can learn to self sooth with your support. Keep going.
Although you have not asked about solids I will mention that introducing solids can also disturb sleep, this may not be the best time to add something additional into the mix - digestion, poos changing, gas...all things which can disturb even the best sleepers. We generally advise solids are not introduced until 6 months - you might want to reconsider and perhaps just wait a few more weeks to start the solids?