Big companies will oppose your trademark over remote similarities, happened to me twice (I will not promote)

I see a lot of posts here about validation and getting customers but not many about trademarks, and in my (very unfortunate) experience they can eat you alive if you are in a competitive category. In 2024 I started working on a chocolate brand. I had the formulation done, branding, samples, marketing copy, website and even branded molds. I paid LegalZoom for a trademark search and still ended up with an opposition from Mars, on the grounds of Velvetiser, a hot chocolate maker they own. I probably could have won, but it would have cost me tens of thousands of dollars to defend a trademark with no goodwill or real demand. After spending a couple thousand in legal fees and over a year and a half of waiting around I decided it was better to let it go. The molds were branded so they were a total loss, I still keep them in my house. The time also killed my desire to pursue this idea. Around the same time, I was working on a meal replacement drink with an off the shelf formulation. Samples, branding, trademark filed, and Nestlé opposed that one too. After spending some more money and facing back-to-back oppositions from major brands, I dropped the brand and the idea. What I learned is that they will aggressively pursue even remote similarities, and a basic search is not going to catch that. On my new project I went with a completely made-up word and filed before spending anything on packaging. Hopefully the third time is the charm. Has anyone here actually fought one of these and won? Should I have kept spending money on the project even in the face of this opposition? I am hoping I just got very unlucky.