You might be overthinking some of your decisions like vendor-lockin, or infrastructure. It should take a bit of research to decide, but those things shouldn't be a big load. Often I make those decisions based on

1) what can we do today?

2) what is hiring going to be like in 1-5 years if we decide to use this technology.

As far as "approving" marketing, etc etc, it's a great opportunity to let you team know that you trust their judgement and delegate. I'm not saying be completely hands off, you're there to review, not do the work, and likely, you aren't and shouldn't be the subject matter expert. Give your feedback, and let the owner know it's up to them (unless you don't trust them in which case you probably have a bigger issue).

Yes, we have to make big and small decisions, understand which are which and delegate those you can. As the founder, you need to set the tone and make sure the right things get done. Those "right things" are probably the hardest to figure out, so hopefully that is the question you are asking.

As a Project Manager years ago I worked for a CEO that struggled to have a consistent and identifiable process and the devs, designer and myself felt the product didn't have direction and we couldn't understand how to decide what was important.

I came up with a simple test to help us decide what is most important, I'd be keen to hear your feedback.

I have started using this in the company I founded and it's not a slam-dunk, but I think it helps.

We'd have a meeting once a month where we'd go through the following questions.

1) Are we living up to our promise? You tell your customers that you do xyz, if you're not able to do those things, then you are not living up to your promise, the priority is to do what is needed so you live up to your promise.

Quick note on this, I think promises should be short and identifiable. At ayvri, we let anybody create amazing user-controlled 3d virtual world scenes just by uploading a gpx or igc file.
That's not our long-term vision, but today that is our promise, so we focus on that.

2) Are you able to effectively demo your product to get customers interested? This goes to starting to get customers or users into your funnel. If you can't give someone a demo and make them interested, how can you expect to get them as customers. Perhaps demo doesn't fit your market, but basically can you get somebody into your funnel.

3) Is there anything preventing a user from going from demo to sale? Pretty simple, are you able to get sales? If not, why not? fix that. It could be missing a billing system (we don't have one yet) it could be missing features, etc. etc. It isn't "what I think we need" because you've already got users in the funnel from the demo, so now you should know. That's why this comes after demo.

4) What can we do to get an extra x% of people into the top of the funnel? There's no point in getting more users in, if you aren't able to convert them in the previous step.

5) Is there anything else we as a team want to do?

So, we would sit in a meeting and go down the list. Before we got to question 3, we would know that we already had enough work for a month, but we kept going through all the questions.

Once we had all the questions answered, we'd have 20 things we needed to work on. From there, we could prioritize and we had a good understanding of the effect different tasks would have on the company.

We may implement a feature that one customer needs so we can get a sale, but we'd understand that doing that comes at the cost of being able to demo effectively until we can get whatever was missing in previous stages up to snuff.

We would also recognize that sometimes there would be something small that we would want to do, or something that would improve virality which was small, and we maybe would decide to do that rather than something else.

As I said, keen to hear how this sits with you and if you find it helpful.