800+ credit score! 🇨🇦 Should I get a second card or wait for a mortgage?

I finally hit the 800+ on my credit score. It took a long time but I’m really proud of the progress!

I’m currently only using one Capital One card, but I’m looking to get a mortgage in the near future (next year or so) Is one credit card enough? I’ve always been nervous about having more than one, but I feel like I’m missing out on better rewards. Is it actually "better" for my credit profile to have two?

Also, will a hard inquiry for a new card hurt my mortgage application, or will a higher total limit help me more in the long run?

If I were to get another credit card, Which is better? I’m torn between the Amex Cobalt for the travel/everyday perks or the CIBC Costco for the 3% back.

I have so many questions and no where to turn. Any advice would be great and much appreciated. Thank you all in advance🙂