It's kind of weird how game promotes changing strategy/figuring out opponent but in reality does everything to prevent it as well..
Not only gold is super limited for majority of the game but the gear is too hard to perfect.. by time you reach 250 glory for the arena champion ending - you will only at most upgrade 2 pieces of legendary equip and that's only IF you go for sexy 4 set.
Overall for those who want to have an easy time - most important step is to buy a buckler, preferably with evasion upgrades... ideally legendary buckler which you can upgrade with a lot of evasion.
Most important mastery with that strategy would be shield mastery. I recommend sword as weapon focus, but it probably can be axe as well, I found sword more reliable due to accuracy being hard to get. As for type of attack - I recommend parry early(get it to level 2 so you can endure early fights) and as you upgrade your buckler with more evasion - swap into the power swing and focus that one.
Out of armor - I prefer the unarmored thing and sexy 4 dancer costume(meaning you want to up relation 3 times in total, likely 2 times on trainer and 1 time on merchant)... this will boost your gold gain massively and allow you to upgrade your weapon and buckler.
Out of relations - focus on trainer first, then once you need to start upgrading you can swap to merchant.. Arena master is kinda pointless, you won't have trouble with accuracy/evasion in this build and it's better to gain permanent one through training anyway.
As you reach end game - it will be easier and easier since even legendary opponents would need all the luck in the world to win.