No worries at all, appreciate your feedback.
To reiterate what we are building, we are not solely building a front end for a block explorer, we are working on several HAF-based dapps (which ship with public hive nodes) and provide public APIs for all devs to use, stemming from hive API nodes. So they are as decentralized as Hive can be.
Block Explorer UI is a front end that is based directly on those APIs. Having multiple options enriches hive ecosystem, which is why all of this work is also open source, so that anyone can spin off a version (currently hivescan.info and explore.openhive.network both run BE UI)
In terms of budgeting, a dev on average costs 3k, that is correct. Infrastructure cost is much lower, and is only needed for additional development and testing servers (mostly for backend devs). The proposal you referenced is actually running some of our backend code, but in a live environment, hence our point above.
No worries about English, you're doing great :)