CloudWatch Evidently Flutter library and payload limitations for batchEvaluateFeature

We are experimenting with Evidently and have loved it so far. I have a couple of questions and clarifications

1. We have a react app and a flutter based app. While I was able to experiment with React using @aws-sdk/client-evidently I could not find a corresponding alternative for Flutter. Do we have one ?
2. Also in comparing to another feature flag product called Flagsmith where we can identify an user with attributes (e.g; country, role, group) at the outset (during login) and then flagsmith will factor in segments and flag values to let us know if the feature is enabled for the given user. WE need to provide user info and attributes only once. However, with evidently I guess we need to pass the entityID and attributes (evaluationContext in EvaluationRequest) to every request to see if a feature is enabled for an user. To overcome this I was combining listFeatures and batchEvaluateFeature to get and filter all the flags enabled for an user on login and then re-use it later. However listFeatures is limited to max of 100 per response (which could be overcome by another query) I feel batchEvaluateFeature is limited to only 20 objects in the payload array which limits the ability for larger projects / products which could have many experiments going on.

Long term: I suggest you either introduce a new method to register the user (entityId) with attributes (evaluationContext) which we could use during login. From then on just querying evaluateFeature(flagName) alone would recognize the user and the context to return if flag is enabled. This would be of significant value to us

(OR)

Interim: In the interim could you at least allow for the batchEvaluateFeature to have 50 or 100 payload (requests: EvaluationRequest[])?

Appreciate your time and help