Why is scrapy so slow when using proxy rotator?

I'm new to scrapy and I'm trying to scrape 300 urls per spider for my project, but for testing purposes, I only scrape 2 urls. When I use proxy rotator it takes 120 secs to 500 secs to finish my script, but when I'm not using proxy it takes 2 to 20 secs to finish my script. Is there any solution that would improve the overall performance of my script? Also, I use proxy rotator from proxyrotator.com

I often get TimeoutError when using proxy rotator. Any advice or answer would be appreciated.

settings.py

#settings.py
ROBOTSTXT_OBEY = False
DOWNLOAD_DELAY = 0.25
RETRY_TIMES = 3
CONNECTION_TIMEOUT = 30
COOKIES_ENABLED = False
DEFAULT_REQUEST_HEADERS = {
    "Accept": "application/json, text/javascript, */*; q=0.01",
    "DNT": "1",
    "Accept-Encoding": "gzip, deflate, br",
    "Accept-Language": "en-GB,en-US;q=0.9,en;q=0.8",
}
CONCURRENT_REQUESTS = 100
CONCURRENT_REQUESTS_PER_DOMAIN = 100
AUTOTHROTTLE_ENABLED = False
DOWNLOAD_TIMEOUT = 30
DOWNLOADER_MIDDLEWARES = {
     'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 400,
}

static_spider.py

class ArticleStaticSpider(scrapy.Spider):
    logfile("server.log", maxBytes=1e6, backupCount=3)
    name = "article_static"

    custom_settings = {
        'ITEM_PIPELINES': {'news_extractor.pipelines.StaticExtractorPipeline': 300},
        "FEEDS": {"articles.json": {"format": "json"}},
    }

    def __init__(self, urls=None):
        self.urls = urls

    def start_requests(self):
        for url in self.urls:
            proxy = get_proxy() # get request for proxy rotator
            ip = proxy['ip']
            port = proxy['port']
            meta_proxy = f"http://{ip}:{port}"
            headers = {
                "User-Agent": proxy['randomUserAgent']
            }
            meta = {
                "proxy": meta_proxy                }
            yield scrapy.Request(url, callback=self.parse,headers=headers, meta=meta, errback=self.errback_httpbin)

    def parse(self, response):                                                                                               
        src = StaticSource(response.url) # module for cleaning html tags
        text_format = src.text
        news = News(response.url, text_format) # module for extracting data
        data = news.generate_data()
        print(data)

scraper.py

from scrapy.crawler import CrawlerProcess
from scrapy.utils.project import get_project_settings
import time

ulrs = [
    "http://www.nytimes.com/2021/02/28/technology/seniors-vaccines-technology.html",
    "http://www.nytimes.com/2021/02/28/us/schools-reopening-philadelphia-parents.html"
]

def main():
    process = CrawlerProcess(get_project_settings())
    process.crawl('article_static', urls=urls)
    process.crawl('article_static', urls=urls)
    process.start()


if __name__ == "__main__":
    t1 = time.perf_counter()
    main()
    t2 = time.perf_counter()
    print(f'Finished in {round(t2-t1, 2)} second(s).....')