Will the bonus round come, and when?
Choosing to spin Gemhalla means accepting that the bonus round may not arrive in a given session. Nobody can predict how often it lands, because every spin is random. The 97.17% RTP describes return over a very large number of spins, not one session. A short session can end far below the bet, and a lucky one far above it.
Deciding how to read the return starts with the RTP version. Gemhalla lists one version, 97.17%, and the game rules show which version a session runs. Check them before the first spin, since the version determines which return applies.
Chasing the top prize misreads Gemhalla. The maximum win is x5,000 the bet, which is A$250,000 at the A$50 top bet, and it is a ceiling reached very rarely. Its size tells you how far a single round can swing, not what you should expect from a session.