V70 II (Diesel) starts badly

Hello, my Volvo has had some cold start problems since the beginning of winter, but I had to org for a few seconds which didn’t make the battery any more. On suspicion I also changed the glow plugs, which have already driven 100,000km, so it was necessary anyway, but this didn’t bring any change. Say: I also had to org a little longer than usual, but it starts after about 6 seconds. Due to the rather high mileage of almost 350. 000km and the knowledge that my moose should last a maximum of one year, however, I did this as a smaller “wehwechen”. A week ago it was then quite frosty outside and also under 0°C. After determined 10 start attempts (each about 10 sec.) I then called the ADAC which had the car with start spray immediately on the run. Now the situation is so that I have to orgle at the cold start each time endlessly long/often until it starts at some point… the starter is completely lost. then once it is at operating temperature, there are no more starting difficulties… but it stands 4, 5 hours the same procedure starts from the front. Is there maybe one or the other component that I could check or exchange on suspicion before I put the moose into the workshop?