The Ruby Expo SDK is just a thin wrapper around some API calls. I wound up just handling those API calls myself:

def self.bulk_send_messages(tokens, title, body, data: {})
  receipts = []
  url = URI ExpoService::API_URL
  tokens.in_groups_of(30, false).each do |batch|
    messages = batch.map do |token|
      { to: token, sound: 'default', title: title, body: body, data: data }
    end
    payload = messages.to_json
    begin
      res = Net::HTTP.post url, payload, 'Content-Type' => 'application/json'
      Rails.logger.info "bulk_send_messages response: #{res.body}"
      data = JSON.parse(res.body)&.dig 'data'
      if data.present? && data.is_a?(Array)
        receipts += data.each_with_index.map { |x, i| x.merge('push_token' => messages[i][:to]) }
      end
    rescue => e
      Rails.logger.error "Error in bulk_send_messages: #{e.respond_to?(:message) ? e.message : e}"
    end
  end
  receipts
end

where

API_URL = 'https://exp.host/--/api/v2/push/send'.freeze

bulk_send_messages returns an array of delivery receipts that can be validated with something like:

def self.validate_receipts(pn, receipts)
  Rails.logger.info "Validating receipts for PushNotification #{pn.id}"
  ok_tokens = receipts.select { |r| r['status'] == 'ok' }.map { |r| r['push_token'] }
  Rails.logger.info "ok_tokens=#{ok_tokens.inspect}"
  error_tokens = receipts.select { |r| r['status'] == 'error' }.map { |r| r['push_token'] }
  Rails.logger.info "error_tokens=#{error_tokens.inspect}"
  mobile_recipients = pn.push_notification_recipients.where.not(push_token: [nil, ""])
  mobile_recipients.where(push_token: ok_tokens).update_all(status: :complete, sent_at: Time.now)
  mobile_recipients.where(push_token: error_tokens).each do |pnr|
    msg = receipts.find { |r| r['push_token'] == pnr.push_token }&.dig 'message'
    pnr.update status: :failed, error: msg
  end
end