To estimate a maximum purchase price for the coin in question, let's consider several factors:

1. Starting Price: 2000 euros. This is the initial price of the auction.
2. Condition: The coin has a condition rating of 95 (S/C-), indicating that it is in very good shape.
3. Auction History:
- In 2020, it was auctioned with a starting price of 3000 euros, but the final price is unknown.
- In 2021, it was auctioned with an estimated price of 3000 euros and sold for 2800 euros.
- In 2022, it was auctioned with a starting price of 2000 euros and sold for 3600 euros.

4. Average Final Price: 3200 euros, indicating that, in general, coins of this reference tend to sell for a price higher than the starting price.

5. Average Starting Price: 2333.33 euros, which is slightly higher than the current starting price.

Given that the coin is in good condition and considering the history of final prices, an estimated maximum purchase price could be positioned in a range between the average final price and the highest recorded final price.

Taking all this into account, a reasonable maximum purchase price could be approximately 3600 euros, which is the highest recorded final price in the past for a coin of similar condition. This also aligns with the estimated price of 3500 euros from the previous auction.