Need your advice on offer selection

Hey folks,

Today was the date of Onboarding for my new job. For the past few weeks, I have given interviews and negotiated with two companies. The later company only matched the first offer so I naturally went with the first one.

Now, on the date of Onboarding, they called me and increased the offer which is making the same interesting.

I have not been given any company's assets on my day 1 today. Can I still make the switch now ? Also need your advice on whether I should switch ?

Thanks in advance.