Actually is there any way to remain at Tier and continue to level up
To avoid tiering up,
- never(!) play any ranked round of the current threshold or better (e.g. stay above 63 scores as a Master),
- never(!) win in rated matchplay against higher tiers,
- never(!) win credits in tournaments,
- play little or no games on mobile.
To level up,
- keep the CDP streak alive at any cost,
- play practice rounds and A/S,
And, concerning your money (tongue in cheek):
- pay for level and XP boosts,
- pay for CC passes to gain the last %% of bonuses.
In one word: Be mediocre, do the grinding, squander your money, miss the fun.