I felt under-leveled and undervalued in my existing org so I interviewed in a top product company and landed an offer. Once I viewed the master class on Taro. I feel it's more than the compensation it's the team and leadership.
How do I politely deny the matched offer?
Congrats on the offer!
I think something like this would suffice: "I really appreciate the effort made to match my outside offer, but after careful consideration, I have decided to take it and part ways with the team. I really appreciate everything you have done for me, but I truly believe that this opportunity is best for my continued growth and career overall."
It's a pretty classic communication technique: Mix negative with positive to avoid burning bridges.
There's a lot of other nuances here with delivery and aspects like body language, so I highly recommend going through my series on Effective Communication to learn more about that.