Congrats! I love cluster too - so I wish you the best of luck reaching rank 54.
I'm not sure whether you're a competitive or cooperative player. If you don't mind cooperative, play Coop Arena during the upcoming Double XP event (a full week) starting on Tuesday. Coop matches max out at 100K during these events (I think comp matches max out at 50K) and while coop matches are longer, it's far easier to consistently get your XP in coop than in comp.
For example, a typical coop arena match takes about 30 minutes...if you're playing with friends and they deilberately let you get more points, you should have no trouble maxing out in most matches. I'd suggest playing on Hard...in my opinion it has a good balance of higher value enemies versus manageability AND you have 15 lives (as opposed to only 10 in crushing).
During double XP events, I might average 25K in competitive matches but in coop, it would be rare that I didn't get at least 90K (often maxing out) - this is even when my teammates are going for points as well. Even if the average comp match lasts only about 10 minutes, I'm still 15-25K ahead with coop when taken match length into consideration AND you're pretty much consistently guaranteed to get your XP in every match.
At your current rank, you require about 200K to go up each time so you should be advancing every 2 or 3 matches. Rank 75 requires 300K XP so even at the higher levels, it will only require 3 maybe 4 matches (and that's if you can't max out). I reckon that with your current XP, it should take about 25-30 coop arena matches during the double XP event to unlock your beloved Cluster Bomb. Can you average playing 2 hours of coop per day over the course of Double XP Week?
But, if you're a better comp player than me, maybe you can max out in every one of those matches and it makes more sense to stick with competitive.
Once I met a handful of friends from the forum here, I started playing with them regularly. They "kindly" told me why I sucked. And explained ways that I could suck less. These days, I'm not too awful. I brought a .5 KDR to around 1.60 and rising. I probably average around that or a little higher in TDM games. But also often go 2-3.
I think comp is a lot more fun then co-op now. And I actually look forward to finding a challenge (not just laggy players, but ones who are actually good without lag). So I recommend finding some good friends to play with. Watch cinemas of players who do well. Ask friends for advice. Etc. Comp has the potential to be a lot of fun.
Im 5th legacy as well. It's crazy how long it takes to level up now.
it really isn't though, once i hit the top level i barely played after that, maybe 2-3 hours a week or none at all (sometimes 2-3 hours a month) yet i'm at still over $30 million atm (so $17.5 million without trying for money and without using negatives) ... really should only take around 2-4 weeks casual amount of playing with double negatives and cash 'em in (most of the time cash 'em in isn't even necessary since you can hit the cap with just the double negatives)
i am absolutely garbage at Competitive i only play Co-op arena after 560 of those i am getting really tired of playing this game because lately people have been leaving the matches just because we die a few times and the game doesnt count what i did in the game and doesnt give me the experience its somewhat frustrating