Client.php

<?php
declare(strict_types=1);

namespace Bitpay\BPCheckout\Model;

use BitPaySDK\Env;
use BitPaySDK\Tokens;
use Magento\Framework\Encryption\EncryptorInterface;
use Magento\Framework\Serialize\Serializer\Json;

class Client
{
    protected Config $config;
    protected EncryptorInterface $encryptor;
    protected Json $serializer;

    public function __construct(
        Config $config,
        EncryptorInterface $encryptor,
        Json $serializer
    ) {
        $this->config = $config;
        $this->encryptor = $encryptor;
        $this->serializer = $serializer;
    }

    /**
     * Initialize bitpay client
     *
     * @return \BitPaySDK\Client
     * @throws \BitPaySDK\Exceptions\BitPayException
     */
    public function initialize(): \BitPaySDK\Client
    {
        $env = $this->config->getBitpayEnv() === 'test' ? Env::TEST : Env::PROD;
        $privateKeyPath = $this->config->getPrivateKeyPath();
        $password = $this->encryptor->decrypt($this->config->getMerchantFacadePassword());
        $tokenData = $this->encryptor->decrypt($this->config->getMerchantTokenData());
        $serializedTokenData = $this->serializer->unserialize($tokenData);
        $merchantToken = $serializedTokenData['data'][0]['token'];
        $tokens = new Tokens($merchantToken);
        $platformInfo = 'BitPay_Magento2_v10.1.0';

        return \BitPaySDK\Client::createWithData($env, $privateKeyPath, $tokens, $password, null, $platformInfo);
    }
}