I'm not an expert as I have questions myself, but what I'm reading in this thread contradicts info discussed in other threads.
Spousal Benefit (both still alive): UP TO 50% of the higher earners PIA. Thats up to 50% of the amount the higher earner gets at FRA. If the higher earner waits until 70, the spousal benefit is still based on the PIA and not the age 70 benefit.
I'm emphasizing UP TO because the spousal benefit is less than 50% if benefits are started before FRA.
https://www.ssa.gov/OACT/quickcalc/spouse.html
Also, you can not start spousal benefits until the higher earner starts their benefit.
Death benefit: Surviving spouse gets the greater of the their own or their spouses benefit.
This is called Survivor benefit, not death benefit. The survivor will only received 100% of the deceased spouse's benefit if the survivor waits until their FRA to claim the Survivor benefit. If they claim prior to their FRA it will be a reduced amount.
https://www.ssa.gov/benefits/survivors/ifyou.html#h6
There are some corner cases where if the high earner spouse started benefits way early the survivor gets a minimum 85% of the high earner benefit but that case is still gray for me.
Re: opensocialsecurity.com It's a great tool. But I've found discrepancies between what it says and what I get from the SSA website. So use it to get a ballpark. "Trust but verify".
I suggest you login to ssa.gov and diddle with the estimated benefit statements and tools. It does not do a great job at spousal benefits because your and your spouses accounts are separate. But your spouses benefit estimate will clear state what you with receive as a death benefit.