Great write up. :)

Your journey is similar to many. In can be addictive prospect and Splinterlands success requires on active investment to get the most out of your experience. The recent changes to rewards will hurt many players with a smaller budget but that can be mitigated by joining a guild and being an active member of the community. Twitch is a great platform of which to do so. There you will find among Splinterlands streamers and viewers a great comradery, the chance to win prizes and opportunity to join guilds with members you come to to know. This is where guilds become advantageous.
Not only Brawling to earn Gladius cards but generally most guilds have a system in place to help some of their weaker members like card delgations and even in-guild prizes. There are many community guilds such as the one I am in, where we don't require set amount of DEC donation only that you stay active in guild and/or in the twitch streams as often as possible (we like to ecourage our members to be part of the wider community as much as possible) and for brawls and contribute what you can spare.
Some other advantages of guild include more DEC per battle win and dicounted purchasing of packs the higher their guild buildings are which is why there is that incentive to continue to contribute to the guild and working together as a team. The faster you can level up buildings, the sooner you get to enjoy increasing benefits. Timezone is usually not a problem in most cases but there are designated guilds of origin where you can join other players from your neck of the world.
Hope that helps with some of your questions. :)