Pedrojorge is 215-130-15 in maximus at 62.3%.
That's a pretty decent ratio to be running. You're still a far way off from retiring due to the number of fights. You're not gonna get to primus with an 80% win ratio or something exceptional like that unless you're willing to sink a lot of trophies into speeding up your glad's development. You can relax a bit - you're doing fine. You can't expect to win them all as some builds are naturally strong/weak against others.
And yes, the competition does get pretty tough in maximus - you're getting to the top competitors and there are a few stables out there that will routinely challenge glad's they can easily beat as they try to rush to primus and stack their win rate.
As Prinny suggested, if there's a particular build you're losing against, or losing due to a particular reason in some cases trying playing with your strategy to account for that, or you can just accept that your glad doesn't shine in that case. Adoede has a great strategy primer in the newbie section that is very helpful. You may also consider changing up some equipment - getting purples, or stacking stamina for example.