I have ideas and solutions to fix the problem

Solution #1: Allowing officers/staff the ability to accept decs (Mentioned in some of the comments on this post)

 Solution #2: Creating a time after a dec is created. For instance, guild1 declares on guild2. Takes the 5 minutes or so it takes for a dec to go through. The dec would stay up for 24-48hrs and then will drop on its own. Now that being said guild1 could just re-dec on guild2. Thats when creating a cool down on specific guilds you can dec on will come into place, or just a normal cool down overall. 

Solution #3: Revert open world pvp back to the way it was because in my opinion I didn't see a problem with it in the first place. Sure being decced on by big guilds and being node camped was slightly frustrating, but its too easy just to spawn town or not pvp. Taking away the inital mechanic this game had on release is kinda stupid in my opinion 

Like these.  I'd structure the timers to allow for reasonable peace from spot griefers - 4 to 6 hours.  Then put a 4 day cool down on them before you can decc the same guild again.,

As a solution to the initial problem of guild war declarations, the hunting NPC that made it easy to find other players has been removed. Now, you have to spend hours searching spots to find them, and if they're in hiding or switch servers, you start over, making it difficult to bully other players. Another method that would affect small guilds of red players or those who abused declarations is to introduce a fee for keeping a war declaration active for 24 hours, for example, 10 million or 20 million from the guild's funds per day. Although not a large sum over time and with multiple active declarations (but this means no longer restricting declarations freely), this fee will bring small guilds to zero funds, requiring good management to continue declaring and having PvP content. In short, this stops the abuse against small players. With these changes and the reintroduction of the free declaration system, we can reintroduce the Duel for Spot (DFS) to maintain some order and diminish player griefing. This also gives us an incentive to play the game and improve our gear to defeat opponents who previously defeated us. Don't always look at it in a negative light. Due to some toxic guilds declaring war on me, I and my guildmates were motivated to grow, and when we managed to beat them, we felt it was worth all the time invested in the game, and we were happy.

@Pearl Abyss, please read these comments where players have joined forces to come up with a solution to make your job easier and to restore the game to what it once was.

Similarly, you could introduce the setting of a guild category where if you are designated as LifeSkill, you do not have permission to participate in node wars/sieges and anything related to PvP, nor can you declare war. Conversely, if you are designated as Combat (PvP), you can only declare war on guilds that are also designated as Combat (PvP), but not on those designated as LifeSkill, thus forfeiting the guild life skill buff, for example. Therefore, if you are set to Combat, you assume that you can be challenged to war as before the changes.

Yes or simply limit the time of

one sided decs