Why offer odds at all? It's both an additional way to attract players and a fairer assessment of their skills. Because in a season, some prefer to play against demonstrably weaker players or within a specific circle. A tournament offers a chance to test your level not only among familiar people but also among those who are leaders on other platforms.
On the other hand, it's reasonable not to offer too high of a multiplier. In my opinion, double the amount is the limit. I proposed fixed odds for simplicity and to attract people to tournaments. My proposal regarding them is described above.